2,256 research outputs found
Few Graphene layer/Carbon-Nanotube composite Grown at CMOS-compatible Temperature
We investigate the growth of the recently demonstrated composite material
composed of vertically aligned carbon nanotubes capped by few graphene layers.
We show that the carbon nanotubes grow epitaxially under the few graphene
layers. By using a catalyst and gaseous carbon precursor different from those
used originally we establish that such unconventional growth mode is not
specific to a precise choice of catalyst-precursor couple. Furthermore, the
composite can be grown using catalyst and temperatures compatible with CMOS
processing (T < 450\degree C).Comment: 4 pages, 4 figure
Split Supersymmetry at the Logarithmic Test of Future Colliders
We consider a large number of pair production processes at future colliders
(LHC, ILC) for values of the c.m. energy in the TeV range, where a logarithmic
expansion of Sudakov kind would provide a reliable description of Split
supersymmetric electroweak effects. We calculate all the leading and next to
leading terms of the expansions, that would differ drastically in the
considered domain from those of an extreme "light" scenario. We imagine then
two possible competitive future situations, at LHC and at ILC, where the
determination of the energy dependence of the cross sections of certain
processes could reveal a "signal" of the correct supersymmetric scheme.Comment: 32 pages, 10 figure
Single production of new gauge bosons from the littlest Higgs model at the energy colliders
In the context of the littlest Higgs(LH) model, we study single production of
the new gauge bosons , and via
collisions and discuss the possibility of detecting these new particles in the
energy collider(). We find that these new particles can
not be detected via the signal in all of the parameter space
preferred by the electroweak precision data. However, the heavy gauge bosons
and may be observed via the decay channel in wide range of the parameter space.Comment: references added, typos corrected. To be published in Phys. Rev.
Sudakov expansions at one loop and beyond for charged scalar and fermion pair production in SUSY models at future Linear Colliders
We consider the high energy behaviour of the amplitudes for pair production
of charged leptons, quarks, Higgs bosons, sleptons, squarks and charginos at
lepton colliders. We give the general expressions of the leading quadratic and
subleading linear logarithms that appear at the one loop level, and derive the
corresponding resummed expansions to \underline{subleading} logarithmic order
accuracy. Under the assumption of a relatively light SUSY scenario and choosing
the MSSM as a specific model, we compare the predictions of the one-loop and of
the resummed expansions at variable energy. We show that the two predictions
are very close in the one TeV regime, but drastically differ in the few ()
TeV range.Comment: 43 pages, 13 Encapsulated PostScript figure
Engagement de groupe, transformation des représentations sociales et modifications comportementales
Dans cette recherche, on s\u27intéresse à la modification d\u27une représentation sociale et à l\u27émission d\u27un comportement. Dans une première condition, les groupes sont composés de personnes « familières », dans la seconde condition, elles ne se connaissent pas. De plus, chaque groupe est divisé en deux sous-groupes, selon qu\u27il y a ou non signature d\u27un document. Il est, ensuite, demandé, aux étudiants, de participer à la mise en place d\u27une campagne de promotion et de valorisation des études. Les résultats montrent des modifications importantes, au niveau des éléments de la représentation sociale, ainsi qu\u27une acceptation plus importante du comportement demandé par l\u27expérimentateur, pour les sujets engagés et familiers. (French
The Mass Splitting Problem
It is discussed the problem of the mass splitting. It is
suggested to use the decay to measure the
mass splitting.Comment: 7 pages, revtex, a few typos fixed, to be published in Pis'ma v
ZHETF, V. 69, No 1, pp. 8-11, 10 January 199
Final-state interaction phase difference in and decays
It is shown that the study of the interference pattern in the
decay provides the evidence
for the large (nearly ) relative phase between the one-photon and the
three-gluon decay amplitudes.Comment: 5 pages, revtex, \tightenlines, a version published in Phys. Rev. D
61, 117504 (2000
Breit - Wigner parameters of nucleon resonance S11(1535)
The result of partial - wave analysis of angular distributions for the
process gamma+p -> eta +p at the energies upto 2 GeV are given. From the energy
dependence of the regression coefficient a0(W) the reliable estimates of Breit
- Wigner parameters of S11(1535) - resonance and energy dependence of real and
imagenery parts of electric dipol amplitude E0+ and its phase were obtainedComment: 12 pages, 11 figure
Monte Carlo Study of the Separation of Energy Scales in Quantum Spin 1/2 Chains with Bond Disorder
One-dimensional Heisenberg spin 1/2 chains with random ferro- and
antiferromagnetic bonds are realized in systems such as . We have investigated numerically the thermodynamic properties of a
generic random bond model and of a realistic model of by the quantum Monte Carlo loop algorithm. For the first time we
demonstrate the separation into three different temperature regimes for the
original Hamiltonian based on an exact treatment, especially we show that the
intermediate temperature regime is well-defined and observable in both the
specific heat and the magnetic susceptibility. The crossover between the
regimes is indicated by peaks in the specific heat. The uniform magnetic
susceptibility shows Curie-like behavior in the high-, intermediate- and
low-temperature regime, with different values of the Curie constant in each
regime. We show that these regimes are overlapping in the realistic model and
give numerical data for the analysis of experimental tests.Comment: 7 pages, 5 eps-figures included, typeset using JPSJ.sty, accepted for
publication in J. Phys. Soc. Jpn. 68, Vol. 3. (1999
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